ludwig457 Group Title Find the area of an equilateral triangle with side of length 18. (Round your answer to one decimal place.) one year ago one year ago

1. ludwig457 Group Title

Area= 1/2 base x height tan(60)=h/18 h=18tan(60) right?

2. ludwig457 Group Title

should i be using law of sines

3. lgbasallote Group Title

why use law of sines?

4. lgbasallote Group Title

wait...by law of sines do you mean $\frac{a}{\sin A} = \frac b{\sin B} = \frac c{\sin C}$

5. ludwig457 Group Title

yes, i have three angles (60) and three sides) so the how would i then find the height

6. lgbasallote Group Title

use pythagorean theorem...you have equilateral triangle |dw:1352707222314:dw|

7. lgbasallote Group Title

so the height would cut your triangle into two equal parts..|dw:1352707262694:dw| can you see how to get the height now?

8. ludwig457 Group Title

15.6?

9. lgbasallote Group Title

yes

10. lgbasallote Group Title

11. ludwig457 Group Title

A=(1/2)(18)15.6)

12. lgbasallote Group Title

yes

13. lgbasallote Group Title

by the way.. you can also use your solution a while ago... 18tan (60) you don't need law of sines...just use a calculator for that

14. ludwig457 Group Title

140.4units squared

15. lgbasallote Group Title

yes

16. ludwig457 Group Title

and that solution from earlier would then give me the height?

17. lgbasallote Group Title

hmm wait...something's wrong with it...let me find it first

18. ludwig457 Group Title

should it be 9 instead of 18

19. lgbasallote Group Title

yes it should be 9